1. Field of the Invention
This invention relates to a structure of mounting an electrical unit on a wall surface (hereinafter referred to as "electrical unit-mounting structure"), which eliminates inconvenience developing between the electrical appliance, mounted on the wall surface such as a ceiling of an automobile, and the wall surface.
2. Background
One conventional structure of mounting an electrical unit on a ceiling as of an automobile is proposed in Japanese Utility Model Unexamined Publication No. 3-66178.
FIG. 9 is an exploded, perspective view of the conventional electrical unit-mounting structure. In FIG. 9, a roof wire harness 31 is secured by clamps 32 to a panel 33 of a vehicle, and then a molded ceiling 34, comprising a foamed material covered with a covering material, is fixedly secured to the vehicle panel 33. At this time, connectors 35, connected respectively to two distal ends of the wire harness 31, are beforehand disposed respectively in openings 34a formed through the molded ceiling 34. Then, the connectors 35 at the distal ends of the wire harness 31 are connected respectively to connection portions 36a of electrical equipments 36 such as room lamps, and the electrical equipments 36 are fixedly secured to the molded ceiling 36 by bolts 37, and a cover 38 is fitted on each electrical equipment 36.
FIG. 10 is a perspective view of an important portion of the conventional electrical unit-mounting structure. In the mounting of an electrical appliance such as an interior lamp, wires hang down during the mounting operation, and hence interferes with this operation. Also, ends of wires, connected to the appliance, and ends of wires connected to a power source are not disposed at constant positions. These cause various inconveniences. To overcome these inconveniences, there has been proposed a method of fixedly securing each connector to the electrical appliance.
As shown in FIG. 10, a connector 42 is connected to an electrical appliance, and has a connector housing 42a in which male connection terminals 42b, fixedly connected respectively to one ends of wires 43a, are received. This connector 42 is retained by mounting members 41a formed on a mounting plate 41 integrally supported on a back side of the electrical appliance 43. A connector 35 connected to a power source is beforehand mounted, and this connector 35 has a connector housing 35a in which female connection terminals (not shown), fixedly connected respectively to one ends of wires 31a connected to the power source, are received. The power source-side connector 35 is fitted into the electrical appliance-side connector 42, and then the mounting plate 41 is fixedly secured to a front face of a molded ceiling 34 at a mounting opening 34a, formed through a predetermined portion of this ceiling 34, by screws or the like passing through respective mounting holes 41b.
In the above conventional construction, however, much time and labor are required for mounting the electrical equipment, and besides the wire harness hangs down during the mounting operation, and the operation can not be easily effected in a narrow space. This has resulted in a problem that the efficiency of the operation can not be enhanced.
Furthermore, from the viewpoint of the operation, the wire harness need to have an excessive length, and therefore it is possible that extra portions of the wires 31a connected to the power source-side connector 35 are held or clamped between the edge of the mounting opening 34a and the mounting plate 41 during the mounting of the mounting plate on the molded ceiling 34.
This has resulted in a problem that the wires connected to the power source are cut, thus causing short-circuiting. And besides, when the wires are thus clamped between the above two portions, the unit is attached to the wall in an incomplete condition, which has invited a problem that the electrical appliance shakes upon application of vibrations and impacts.